Valid
The :valid CSS pseudo-class stands for any element like <input> or <form> the contents of which are successfully validated. This helps in simplifying the valid fields’ adoption of an appearance that allows users to confirm the proper formatting of their data.
Cascading Style Sheets or CSS is used by web developers to alter the appearance of an HTML element, A valid CSS pseudo-class follows CSS syntax standards and rules, and makes sure that the formatting is accurate and free of errors so that they can be properly interpreted by browsers.
Pseudo-classes are useful in applying the desired styles as per specific user interactions, conditions, and characteristics. For example, the appearance of a clickable button can be changed when users hover on it. It also helps in highlighting the right fields for the visitor. When you are given a form to fill, for example, if you leave mandatory fields empty, they are highlighted, and you are not allowed to proceed further. It becomes ‘valid’ once you enter something in that field. Another example is the green colour which is normally used to indicate valid fields. A colour-blind person may be unable to distinguish between colours, and hence, an additional indicator, like some descriptive text, is used to convey the same message.
The :valid pseudoclass thus enables user-friendly design and makes a website more responsive.